Effects of post annealing on the physical and electrical properties of solar-blind polycrystalline gallium oxide (Ga2O3) ultraviolet photodetectors on the sapphire substrate are investigated. The grain size of poly-Ga2O3 becomes larger with the post annealing temperature (PAT) increasing from 800 °C to 1000 °C, but it gets smaller with further raising PAT to 1100 °C. A blue shift is observed at the absorption edge of the transmittance spectra of Ga2O3 on sapphire as increasing PAT, due to the incorporation of Al from the sapphire substrate into Ga2O3 to form (AlxGa1-x)2O3. The high-resolution X-ray diffraction and transmittance spectra measurement indicate that the substitutional Al composition and bandgap of (AlxGa1-x)2O3 annealed at 1100 °C can be above 0.30 and 5.10 eV, respectively. The Rmax of the sample annealed at 1000 °C increases about 500% compared to the as-deposited device, and the sample annealed at 1000 °C has short rise time and decay time of 0.148 s and 0.067 s, respectively. This work may pave a way for the fabrication of poly-Ga2O3 ultraviolet photodetector and find a method to improve responsivity and speed of response.

中文翻译：

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后退火对蓝宝石上多晶Ga2O3光电探测器电性能的影响。

研究了后退火对蓝宝石衬底上的日盲多晶氧化镓（Ga2O3）紫外光电探测器的物理和电学性能的影响。随着后退火温度（PAT）从800°C升高到1000°C，聚Ga2O3的晶粒尺寸变大，但随着PAT进一步升高到1100°C，其晶粒尺寸变小。随着PAT的增加，在蓝宝石上Ga2O3的透射光谱的吸收边缘观察到蓝移，这是由于将铝从蓝宝石衬底中掺入到Ga2O3中以形成（AlxGa1-x）2O3。高分辨率X射线衍射和透射光谱测量表明，在1100°C退火的（AlxGa1-x）2O3的替代Al组成和带隙分别可以高于0.30和5.10 eV。与沉积后的器件相比，在1000°C退火的样品的Rmax增加约500％，并且在1000°C退火的样品的上升时间和衰减时间分别较短，分别为0.148 s和0.067 s。这项工作可以为制造聚-Ga2O3紫外光电探测器铺平道路，并找到一种提高响应度和响应速度的方法。